Shadow Generation Apparatus and Method

ABSTRACT

Apparatus and a method for generating a shadow onto a real world surface is described, with the shadow being related to a virtual object in for example a game world. The apparatus ( 24 ) comprises a light source ( 26 ), receiving means ( 28 ) for receiving a real world description, and shadow generation control means ( 30 ) which control the light source to generate a shadow for projection onto the real world surface ( 18 ) in dependence on the received real world description. Hence, apparatus that delivers shadow effects in a room in order to enhance a gaming or movie watching experience is provided.

This invention relates to apparatus and a method for providing realworld visual cues to a user. In particular this invention relates toapparatus adapted to deliver shadow effects in a room to enhance agaming experience. The invention has particular, but not exclusive,application to computer gaming and home theatre systems.

Patent application WO 02/092183 describes a real world representationsystem and language in which a set of devices are operated according toa received real world description and hence render the real worldexperience to the user. For example the devices may output visible colortones and luminance onto the walls of a private dwelling in dependenceon the received description. The description may be embedded or providedwith a broadcast signal thereby linking the description to audio/visualcontent within the broadcast. Hence an ambient immersive environment iscreated, which is flexible, scalable and provides an enhanced experienceto a user.

Patent application WO 02/092182 in particular describes the applicationof the concepts described in WO 02/092183 in a gaming environmentthereby rendering in the real world, in real time, effects related tothe game world model displayed for example on a display. Effects such aslighting levels, (relative/absolute, moods, colors, position, focus) andmood—emotional, ambient, animated and so on are disclosed. In oneexample, the real-world description reads <FOREST>, <SUMMER>, <EVENING>,which is interpreted into specific instructions relating to the colortones and luminance level required, such as a color tone of a pleasantgreen and the light level low but warm. Hence, such an environment inthe game world may be rendered in the real world providing an enhancedgame playing experience.

It is also common to provide real time shadows for virtual objects inaccordance with virtual lighting conditions within a virtual environmentsuch as a displayed computer game, as described in EP0948978. Suchshadows provide a visual cue as to the virtual position of the object inthe virtual world to the game player. Such shadows also serve toreinforce the perceived “presence” of an object in a virtual world.

However, it may be that such visual cues may be useful in the realworld, for example in circumstances where objects not within the gamecharacters displayed field of view are present.

There is therefore a desire to provide apparatus and a method capable ofproviding real world shadow effects in a gaming or home theatreapplication.

According to a first aspect of the invention, there is providedapparatus for projecting a shadow related to a virtual object present ina virtual world, onto a real world surface, comprising a light source,receiving means for receiving a real world description, and shadowgeneration control means which control the light source to generate ashadow for projection onto the real world surface in dependence on thereceived real world description. According to a second aspect of theinvention, there is provided a method for providing a real world shadoweffect related to a virtual object, comprising receiving a real worlddescription in the form of an instruction set of a markup language, andcontrolling a light source to generate a shadow in dependence on thereceived real world description.

Owing to the invention, it is possible to provide a real world shadoweffect associated with for example a monster in a computer game, therebyproviding an enhanced experience. For example, a monster located“behind” the game character in the game world, may cast a shadow ontothe real wall in front or to the side of the user, thereby alerting theuser controlling the game character that something nasty is “behind”him. Alternatively, an aeroplane flying overhead in a movie or game maycast a shadow onto the floor or across a wall in front of the user.

The game may have the real world description encoded within it toprovide to the shadow apparatus, or a software engine or browser such asthat described in WO 02/092182 may analyze the game world and objectstherein and hence provide the real world description to the apparatus.Alternatively, a broadcast may provide the real world description inaddition to the audio/video stream, or the video stream may be analyzedas described in WO 02/092182.

In one embodiment of the first aspect, the shadow effect is generated byapparatus comprising a small array of light emitting diodes withsuitable lens for projection. Advantageously, only a relatively lowresolution array is required since having a rather fuzzy, orindistinctly edged shadow adds to the experience since it is mostly theusers peripheral vision that picks up the shadow. Hence a compact andrelatively inexpensive peripheral may be provided to enhance a gameplaying or movie watching experience. In another embodiment of the firstaspect, apparatus in the form of a liquid crystal display projector isprovided with control means to generate a shadow effect in dependence onthe real world description.

Embodiments of the invention will now be described, by way of exampleonly, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic perspective view of a real world representationsystem including shadow generating apparatus,

FIG. 2 shows example set up views of the system,

FIG. 3 illustrates an embodiment of shadow generating apparatus inoperation,

FIG. 4 illustrates another embodiment of shadow generating apparatus inoperation, and

FIG. 5 illustrates a low resolution shadow moving from left to right.

FIG. 1 illustrates a real world representation system comprising a setof devices including a computer with display device 10, audio speakers12, a lighting device 14, a heating device 16, walls 18, floor 20. Thesedevices together contribute to make up the ambient environment, eachdevice being arranged to provide one or more real-world parameters. Forexample, the lighting device 14 contributes color tones as well as tothe luminance level. The devices may be electronic or they may be purelymechanical. The devices are interconnected by either a wireless networkor a wired network such as a powerline carrier network. Of course theenvironment may include normal furniture 22. The computer may be aso-called “media-PC” enabling computing, gaming and audio/video hometheatre applications.

At least one of the devices making up the real-world representationsystem is arranged to receive a real-world description in the form of aninstruction set of a markup language, the devices being operatedaccording to said description. In this example, this descriptionaugments a computer game that a user is playing on computer 10. Asdifferent environments are encountered by the user's character, adescription generated by computer 10 is transmitted to the devices inthe system. The devices then render this description onto the real worldenvironment of FIG. 1.

For a full description of the aspects of operation of such a real worldsystem and real world description language, the reader is directed topublished patent applications WO 02/092183 and WO 02/092182.

The system also includes shadow generating apparatus 24 (shown in moredetail in FIGS. 2, 3 and 4) which is real world markup language enabled,and hence serves to increase the functionality of the real-worldrepresentation system. A user would purchase the shadow generatingapparatus 24 to improve their enjoyment of, for example, a game thatincludes a real world description in the form of an instruction set of amarkup language. The shadow generating apparatus 24 is arranged toprovide extra functionality to a game in response to the receivedinstruction set.

FIGS. 2 a and 2 b illustrate by way of example two possible arrangementsfor the shadow generation apparatus 24 in the real world environment.

The apparatus 24 comprises a light source 26 and receiving means 28 forreceiving a real-world description in the form of an instruction set ofa markup language via the wired or wireless network mentioned above. Theapparatus further comprises shadow generation control means 30 forcontrolling the apparatus to generate a shadow 34 for projection vialight source 26 in response to a received instruction.

The apparatus 24 may comprise a liquid crystal based projector withcontrol means 30 in the form of a computer program and processor with asoftware device driver. Alternatively, the apparatus 24 may comprise arelatively inexpensive light emitting diode array provided with suitablelenses and control means in the form of a processor and software devicedriver.

FIG. 2 a illustrates apparatus 24 arranged behind the user who isplaying a game on computer 10. In FIG. 2 a the apparatus may be ceilingor wall mounted. Suppose an enemy or monster is creeping up to the usercontrolled game character in the gameworld of computer 10. The apparatusoperates according to the following example method. It receives via 28 areal world description in the form of a mark-up language, for example<shadow> <middle>. Control means 30 controls light source 26 to preventlight output in middle region 34 therefore causing a shadow 34 to bedisplayed on the wall in front of the user, providing a peripheralvisual cue in the form of a shadow to the user that something isdirectly behind the character in the game world.

Other instructions relating to the relative size and position of theshadow may be received thereby creating a dynamic shadow effect for theuser. For example, a template of shadow shapes associated with the realworld description may be utilized in the controlling of the light sourceto generate the shadow effect (see FIG. 5).

FIG. 2 b illustrates the apparatus 24 positioned in front of the userwhilst still projecting a shadow 34 onto the wall 18. Hence theapparatus may be relatively portable and may sit on a table or deskbeside or behind the user, depending on the relative distances involvedin the users ambient experience enabled environment.

FIG. 3 shows in more detail an embodiment of apparatus 24. The apparatuscomprises a light source 26 comprising an individually addressable arrayof individually addressable light emitting diodes (LED), of which onlyfour are shown for clarity in the Figure. Each LED 26 a-d has arespective associated lens 40 for projection, such as a fresnel lens.Those skilled in the art will recognize that other standard opticalelements and components may be utilized to achieve shadow projectionover the required distances. Control means 30 receives instruction viameans 28 (here shown as a wireless antenna by way of example) and causessome of the LEDs to be switched off, or at a low light intensity level,whilst others are switched on to emit light. Hence, as shown in theFigure, LED 26 a and LED 26 d are on and emitting light 42, whilst LED26 b and 26 c are switched off creating a shadow 34 on wall 18.

Experiments have shown that since the shadow is in the peripheral visionof the user, the shadow does not need to be of high resolution. In fact,fuzzy or indistinct edges appear to add to the atmosphere, and in factan indistinct shape may be used and is adequate for fast objects such asaeroplanes which zoom overhead in the game world. Hence simple shadowtemplates for game characters, monsters, and other objects may beprovided leading to reduced computing and control complexity, whilststill adding significantly to the atmosphere and experience of the user.

Furthermore, the low resolution requirements enable a small andinexpensive LED array to be used, such as a 10—10 array up to say100×100 LEDs for example. Hence reasonably inexpensive, and portableshadow generation apparatus may be obtained.

FIG. 4 illustrates apparatus 24 in which a liquid crystal display (LCD)projector supplied with control means 30 is utilized. In this embodimentthe liquid crystal display 44 comprises many pixels of which only fiveare shown schematically in the Figure for clarity. Control means 30drives the display so that some pixels 44 a, 44 b emit light whilst somepixels 44 c, 44 d, 44 e block light causing a shadow region 34 on wall18.

The control means 30 in this embodiment may be provided within theapparatus 24, and may be in the form of a computer program and softwaredevice driver which receives the real world description, interprets itand controls the data written onto the LCD for output. Alternatively thecomputer 10 may directly drive the LCD for output. Hence, more complexgeometric shadow shapes may be displayed by such apparatus, although asmentioned previously such shadows need not be sharp with detailed edgesfor the immersion effect to operate.

The description of the real-world experiences including shadowinformation relating to a virtual object in a game or video world isprovided by a markup language that communicates a description ofphysical environments and the objects within them, their relationship tothe user, each other and to the physical space. Within a location thatis enabled to produce a real-world experience, the instruction set ofthe markup language is interpreted by a device or devices to render theexperience.

For example, FIG. 5 illustrates a moving projected low resolution shadow34 on the wall 18 representing perhaps a monster in the game world.Parts a, b and c of the Figure illustrate how the shadow may appear tomove from left (a) to the middle (b) to the right (c) edge of the wallin response to the received real world description. The tiles in eachpart of the Figure represents the output of an LED for example, or of anarea of a liquid crystal display and hence illustrates how a lowresolution shadow may be generated and yet still appear convincing.

As mentioned previously, a template of such shadows may be providedeither within the device or loaded into computer 10, thereby keepingprocessing and computing requirements to a reasonable level in contrastwith the real time generation of game world shadows appreciated by thoseskilled in the art.

Whilst the invention has been described above in relation to projectinga shadow onto a real world surface, those skilled in the art willappreciate that a display enabled real world surface (for example a wallscreen or a wall with a large display built into it) may also becontrolled to generate and display a shadow, although this embodimenthas a disadvantage in that the positioning of the computer 10 will bedictated by the non-portable fixed real world display surface for shadoweffects.

1. Apparatus for projecting a shadow related to a virtual object, onto areal world surface, comprising a light source, receiving means forreceiving a real world description, and shadow generation control meanswhich control the light source to generate a shadow for projection ontothe real world surface in dependence on the received real worlddescription.
 2. Apparatus as claimed in claim 1, wherein the lightsource comprises a plurality of addressable light emitting diodes, eachof which outputs through a respective lens for projection.
 3. Apparatusas claimed in claim 2, wherein each respective lens is a fresnel lens.4. Apparatus as claimed in claim 2, wherein the shadow generationcontrol means selectively addresses each light emitting diode independence on the received real world description to generate the shadowfor projection.
 5. Apparatus according to claim 1, wherein the apparatuscomprises a liquid crystal display projector.
 6. Apparatus according toclaim 5, wherein the shadow generation control means selectivelyaddresses the pixels of the display to generate the shadow forprojection.
 7. Apparatus according to claim 1, wherein the received realworld description is in the form of an instruction set of a markuplanguage.
 8. Apparatus according to claim 1, wherein the received realworld description includes location information.
 9. Apparatus accordingto claim 1, wherein said real world surface comprises display means. 10.A method for providing a real world shadow effect related to a virtualobject, comprising receiving a real world description in the form of aninstruction set of a markup language, and controlling a light source togenerate a shadow in dependence on the received real world description.11. A method according to claim 10, wherein a template of shadow shapesassociated with the real world description is used in said controllingof the light source to generate said shadow effect.